tomney



2 Sheets-Sheet 2.

A (No Model.)

J TOMNEY ELECTRIC BURGLAR ALARM.`

Patented Deo. 4, ,1883.,7'

IVy PETERS. Pboblilhographcr. Washingbn,

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PArnNr JAMES TOMNEY, OF NEV YORK, N., Y.

ELECTRIC BURGLAR-ALARIVI.

SPECIFICATION forming part of Letters Patent No. 289,471, dated December 4, 18,83. vApplication filed February 5, 1883. (No model.)V

, in the office and capable of giving an alarm on a change of resistancein the circuit, a number of different Vresistance devices located at a guarded structure, and a mechanism located at a guarded structure whereby these resistance devices may be successively introduced for a desired periodinto the electric circuit, so that even if aburglar should obtain knowledge as to what resistance was in the electric circuit at the time of closing the guarded structure, such knowledge would be rendered of no avail to him because of the periodical changing of the resistance. y

The mechanism employed may consist of a train of wheels impelled by a spring or weight and controlled at the oflice by means of an electro-magnet located at the guarded structure; or it may consist of a train of wheels located at the guarded structure and adapted to run constantly or for any desired periods.

In the accompanying drawings, Figurel is a diagram illustrating an electric burglar-alarm embodying my improvement, and Fig. 2 is a diagram illustrating a burglar-alarm having the improvement embodied in it in a modied form.

Similar letters of reference designate corresponding parts in both figures.

A designates the main battery, located at the office where watch is kept. One pole is connected by a wire, B, to an earth-plate, C, and

the other pole is connected by awire, B', with one of the contact-pieces, a, of a metallic switch, D. From theswitch Da wire, B2, extends to one end of the coils of a galvanometer, E. From'the other end ofthe coils of this galvanometer a wire, B, extends to the guarded structure.

A designates a battery located in the office l cuit.

wheels.

and of greater electro-motive force than the battery A. One pole is connected by a wire, Bt, with an earth-plate, C. The other pole of this battery is connected by a wire, B5., with `the contact-piece a of the switch l). By manipulating this switch either the battery A or A may be connected with the electric burglaralarm. To the pivot of the needle of the galvanometer is connectedone end of a wire, B, forming a local circuit, the other end of said wire being connected with two contact-pieces, b, with which the needle makes contact when vibrated` sufficiently, thereby closing the cirrlhis local circuit is provided with a battery, A2, and an electro-magnetic bell, F,

which is caused to ring upon the closing of y the circuit. The contact-pieces b l are shown as consisting of screws inserted through posts wherein they are adjustable.

The wire B3 is connected at the guarded structure to one end of the coils of an electromagnet, G, which controls the operation of a mechanism, H,whereby a number of resistance devices, I 12 I3 I* I5 I, are successively introduced into the electric circuit at the guarded structure. rlhis mechanism consists, essentially, of a train of gear-wheels, o c", which are rotated by a weight or a spring under control of the electro-magnets G. I combine with the train of wheels an escapement or a fly, e, to prevent them from rotating too rapidly. On one side of the wheel c is a pin, f. A lever,

g, is pivoted to the frame of the train of wheels, i

and is affixed at one end to the armature of the electro-magnets G. rlhe other end of the lever extends close to the wheel c', and'when the armature of the electro-magnets is not attraeted thereby this end of the lever is actuated by a spring, so as to obtrude itself in the path of the pin j and block the train of Vhen the armature of the electromagnets is attracted bythem,the lever is moved out of the path of the pin fand the train of wheels is free to rotate under the inuence of their spring. rllhe battery A is not capable of energizing the electro-magnets G to an extent sufcient to cause them to attract their armature; therefore, whenthe watchman at the ofiice desires to cause the said electro-magnets to attract the armature he switches on -the batteryA. This battery is only left 'on momen- IOO tarily; hence the electro-magnets attract their armature and then immediately release it, thereby freeing the train of wheels from the lever and allowing the lever to obtrude itself again in the path of the pinj'. The train of wheels is therefore allowed to run only long enough for the wheel c to make a single revolution. If the wheel c were provided with two or more pins, j", it could be blocked and stopped after making a part of a revolution.

The resistances I I2 I I'L I5 I in this example of my invention consist of coils of wire. These coils of wire at one end are connected to a wire, Bl, which leadsto an earth-plate, C2.

yAt the other end they are severally connected to contact-pieces Jl J2 J3 J" J5 J, consisting7 as here shown, of metallic springs arranged upon a disk, K, of wood or other suitable insulating material. Through this disk K eX- tends the shaft of one of the wheels c. This shaft is provided with a metal linger, c, which, as the shaft rotates, successively impinges against the contact-pieces J J 2 J3J4JJ5. This finger is in circuit, owing to the connection of the coils of the electro-magnet Gby means of a wire, B8, with theframe ofthe train of wheels, the frame, the wheels, and theirshafts being made of metal. Each time the electro-magnets' G permit the train of wheels to rotate, the shaft to which the finger c is afiixed carries the said finger far enough to break Contact with one of the contact-pieces J J 2, &c., and make contact withthe next of said contactpie/ces, thereby cutting out one resistance-coil and introducing another. The resistancecoil so introduced into the electric circuit is retained in the electric circuit after the lever g resumes its normal position and until the train of wheels are permitted to rotate again. All the resistance-coils may, if desired, be arranged in one spool.

The variation between the resistances IIg, &c., may be so slight that a change from one to another in the main circuit will not effect the closing of the local circuit and cause the bell F to ring. Generally, however, it will be much greater. Then, the contact-pieces b of the galvanometer in the local circuit will be made adjustable, and can be moved to any position desired-for instance, if the premises were closed up with a resistance in circuit that would cause the galvanometer-needle to stand midway between the contactpieces, the contact-pieces on each side being adjusted to allow the needle a swing of six points on a scale, and the operator at a later l hour desires to place a different resistance the adjustment of the contact-pieces will then be made to correspond with the-new position of the needle. It will be better to break the local circuit by a switch or key provided forv the purpose before changing the resistance, so that the galvanometer will not .sound an alarm, even if its needle should be deflected so as to touch a contact-piece before the adjustment of the latter. v

It is obvious that by means of this improvement the watchman atthe office may effect a change in the resistance in the guarded structure at will, and by doing so with sufficient frequency can frustrate the efforts of a burglar having knowledge of the resistance in the. circuit at the guarded structure at the time of closing the same, to gain access to the guarded structure.

If preferable, an electro -magnetic mechanism may be substituted for the train of wheels, their operating-spring and the electro-magnets for controlling the same. Indeed, I may use in lieu of either, if desirable, a mechanism adapted to run continuously or during any desired periods, and to change the resistance in the electric circuit periodically. This would not be under the control of the operator, and, if not run constantly, would need to be started by the inmates of the guarded structure just preparatory to their leaving the structure.

I have shown in Fig. 2 a piece of mechanism in aguarded structure, resembling a clock in so far as it has a train of wheels impelled by a spring or weight, and a spindle carrying a finger or hand, c2, around in a circular path. This hand is of metal, and the wire B3 is connected to it or its spindle. As it travels around it successively makes contact with contactpieces J J2, 81e., arranged on a disk and insulated from each other. Wires connect these contact-pieces with different resistances I I, &c., and the latter are connected by other wires to a common wire, B7, leading to an earthplate, G2.

Although I have represented my invention in connection with a single-guarded structure, I intend to use it in conjunction with anumber of guarded structures connected to a single IOO IIO

ofice, the mechanism described, the main cirnation of a galvanometer or other device located at an office or place where watch is kept,- and capable of giving an alarm on a certain change of resistance in the circuit, a number of different resistance devices located at a guarded structure, and a mechanism, also located in the .guarded structure, Wherebythe troduced into the electric circuit, and electro- 15 magnets for controlling said mechanism," substantially as specified.

3. A mechanism consisting` of a train of Wheels, a Weight or spring for actuating the train of Wheels, electro-magnets for controlling the operation of the said Wheels, a series of resistance devices and means for bringing any of `these resistance devices into circuit, substantially as speciied.

- JAS. TOMNEY.

Vitnesses: y l t T. J. KEANE,

J MES R. BOWEN. 

